Electrical connector for printed circuit boards

ABSTRACT

The object of the present invention is to provide an electrical connector which makes it possible for the contacts to electrically contact each other with a high contact pressure even when the contacts are made smaller and shorter. Contacts (40) and (80) which electrically contact each other are respectively secured in housings of a plug connector (20) and a cap connector (60), with the contacts being positioned in two rows in each connector. When the plug connector (20) and cap connector (60) are connected, first and second spring members (42) and (44) of the contacts (40) are clamped between wall surfaces (38a) and (38b) of the housing (30) and contact section (82) of the contacts (80), so that the contacts (40) and (80) are springably pressed strongly against each other.

FIELD OF THE INVENTION

The present invention concerns an electrical connector equipped with twoconnector halves that are respectively mounted on different boards andconnect these boards to each other.

BACKGROUND OF THE INVENTION

In the past, electrical connectors have been widely used in order toconnect printed circuit boards, hereafter referred to as "PCB's", toeach other. Such electrical connectors as disclosed in U.S. Pat. No.5,224,866 are equipped with a plug connector and a cap connector thatare mounted on different boards and are connected to each other. ThePCB's are connected to each other by connecting the plug connector andcap connector. The plug connector and cap connector each have aplurality of contacts and a housing in which these contacts are lined upat a given pitch. Ordinarily, the contacts lined up in the housing ofthe plug connector possess spring forces, so that when the plugconnector and cap connector are connected, the contacts lined up in therespective housings are caused to contact each other with a given forceas a result of these spring forces, thus establishing an electricalconnection.

As a result of the miniaturization of electrical connectors in recentyears, there has been a tendency for the contacts to become smaller andfor the pitch at which the contacts are lined up to become narrower.Furthermore, there has also been a tendency for the contacts to becomeshorter, in order to reduce the distance between the connected boardswhen the boards are connected face-to-face by such an electricalconnector. In cases where the contacts are thus made smaller andshorter, the spring forces of the contacts drops so that there is a dropin the contact pressure between the contacts, thus leading to the dangerof an inadequate electrical connection.

U.S. Pat. No. 5,224,866 discloses an electrical connector assembly forelectrical connection to conductive pads on board members including plugand receptacle connectors. Each connector has electrical terminalssecured in a housing, the terminals including contact sections andtermination sections for electrical connection to the conductive pads onone of the board members. The terminals in the receptacle or capconnector have a linear configuration secured in the housing and includecontact sections for electrically connecting with the contact sectionsof the plug connector when the plug connector and receptacle connectorare mated together.

The object of the present invention is to provide an electricalconnector that makes it possible to cause the respective terminals orcontacts to electrically and mechanically engage each other with a highcontact pressure even if the contacts are made smaller or shorter.

The electrical connector of the present invention, which is used inorder to achieve the above mentioned object, is an electrical connectorthat is equipped with a plug connector and a cap connector in which theplug of first contacts and the cap or second contacts that contact eachother are respectively aligned. The connectors are respectively mountedon a first board and a second board and connect the first board andsecond board to each other.

The electrical connector for electrical connection to conductive pads onboard members comprises a plug connector having first electricalcontacts secure din a plug housing and including contact sections andtermination sections for electrical connection to the conductive pads onone of the board members and a cap connector having second electricalcontacts with a linear configuration secured in a cap housing andincluding contact sections electrically connecting with the contactsections of the plug connector when the plug connector and cap connectorare mated together and termination sections for electrically connectingwith the conductive pads of the other of the board members. Theconnector is characterized in that: each contact of the plug connectorincludes a base portion having a beam extending upwardly therefrom, thebeam including a contact section thereon for mating with a correspondinglinear contact of the cap connector. The beam further includes anS-shaped spring portion extending from the end thereof, the springportion extending to an end portion that is substantially at the sameheight as the contact section on the upstanding beam. Upon mating theplug and cap connectors, the spring end portion presses against acentral wall of the plug connector such that the S-shape contactsections of the plug connector are springably clamped between the linearcontact sections of the cap connector and the wall of the plug housing.

As a result, even if the contacts are made smaller and shorter in orderto reduce the pitch of the contacts, the first or plug contacts andsecond or cap contacts can be caused to wipingly contact each other witha high contact pressure. Furthermore, the first contacts are lined up intwo rows so that the S-shaped spring members are mutually symmetrical inthe opposing rows. As a result, the respective forces from the wallsurfaces and the second contacts are balanced between the two rows, sothat the first contacts and second contacts can be caused to contacteach other with a high well-balanced contact pressure. Thus, anelectrical connector that provides a secure electrical connection can beobtained.

Embodiments of the electrical connector of the present invention willnow be described by way of example with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1-4 illustrate the plug connector in a first embodiment of theelectrical connector of the present invention. FIG. 1 is a plan view,FIG. 2 is a side view, FIG. 3 is an end view, and FIG. 4 is a schematicplan view of a board on which the plug connector is mounted.

FIG. 5 is a cross-sectional view of the plug connector shown in FIGS.1-4.

FIGS. 6-9 illustrate the cap connector of the electrical connector ofthe present invention. FIG. 6 is a plan view, FIG. 7 is a side view,FIG. 8 is an end view, and FIG. 9 is a schematic plan view of a board onwhich the cap connector is mounted.

FIG. 10 is a cross-sectional view of the cap connector shown in FIGS.6-9.

FIG. 11 is a cross-sectional view that illustrates the connected stateof the plug connector shown in FIGS. 1-4 and the cap connector shown inFIGS. 6-9.

FIGS. 12-14 illustrate the cap connector in a second embodiment of theelectrical connector of the present invention. FIG. 12 is a plant view,FIG. 13 is a side view, and FIG. 14 is an end view.

FIG. 15 is a cross-sectional view of the cap connector shown in FIGS.12-14.

FIG. 16 is a side view that illustrates the cap connector in a thirdembodiment of the electrical connector of the present invention.

FIG. 17 is a cross-sectional view that shows the cap connector in FIG.16 connected with a plug connector, illustrating the electrical contactbetween the ground contacts of the cap connector and the ground contactsof the plug connector.

FIG. 18 is a cross-sectional view that shows the cap connector in FIG.16 connected with a plug connector, illustrating the electrical contactbetween the signal contacts of the cap connector and the signal contactsof the plug connector.

FIG. 19 is a side view that illustrates the cap connector in a fourthembodiment of the electrical connector of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

A first embodiment of the electrical connector of the present inventionwill be described with reference to FIGS. 1 through 11.

FIGS. 1-5 illustrate the plug connector of the electrical connector. Aplug connector is one example of the connector referred to as the "firstconnector" in the present invention. FIGS. 6-10 illustrate the capconnector. A cap connector is one example of the connector referred toas the "second connector" in the present invention. FIG. 11 shows theplug connector and cap connector connected to each other.

The electrical connector 10 (FIG. 11) has a plug connector 20 and a capconnector 60 that are connected to each other. The plug connector 20 ismounted on a board 12, and the cap connector 60 is mounted on a board14. When the plug connector 20 and cap connector 60 are connected toeach other, the boards 12 and 14 are connected to each otherface-to-face as shown in FIG. 11.

The plug connector 20 (FIGS. 1-5) is equipped with a housing 30 andcontacts 40. The contacts 40 have projections 41, for press fitting intocontact-receiving cavities of the housing 30 so as to be fastened to thehousing 30, and they are aligned in two rows in the direction of thelength of the housing 30. The housing 30 has posts 32 and 34 that arerespectively inserted into post holes 12a, 12b formed in the board 12and a metal-fastening fitting or hold down 36 that is soldered to afastening pads 12c on the board 12. Furthermore, a central wall 38 thatextends in the direction of the length of the housing 30 is formed inthe central part of the housing 30. This central wall 28 has two wallsurfaces 38a and 38b. Contacts 40 are comprised of contact sections 41including S-shaped first spring members 42 that have two bent portions42a and 42b, second spring members 44 that have contact projections 44awhich electrically contact the contact sections 82 of contacts 80described later, and termination sections 46 that are soldered toconductive pads 12d on the board 12. The contact legs 42c of the firstspring members 42 substantially contact the wall surfaces 38a and 38b,while the second spring members 44 via contact projections 44a contactthe contact sections 82 of the contacts 80. The contacts 40 are formedby stamping from single metal plates, which are superior in terms ofconductivity and spring characteristics. The contacts 40 are installedat a pitch of 0.6 mm, and the height of the contacts 40 from the board12 is approximately 3.00 mm.

The cap connector 60 is equipped with a housing 70 and contacts 80. Thecontacts 80 are lined up in two rows along the length of the housing 70.The housing 70 is equipped with posts 72 and 74 as shown in FIG. 7 thatare respectively inserted into post holes 14a and 14b formed in theboard 14, and a metal-fastening fitting or hold down 76 that is solderedto a fastening pad 14c on the board 14. Furthermore, side walls 78,which extend in the direction of length of the housing 70, are formed onboth side portions of the housing 70. Contacts 80 are comprised ofcontact sections 82 that electrically contact the contact projections44a of the second spring members 44 of the contacts 40 and terminationsections 84 that are soldered to conductive pads 14d on the board 14.The contacts 80 are formed by stamping and bending single metal plates,which are superior in terms of conductivity and spring characteristics.The contacts 80 are installed at a pitch of 0.6 mm, and the height ofthe contacts 80 from the board 14 is approximately 3.0 mm.

When the plug connector 20 and cap connector 60 are connected, as shownin FIG. 11, the first and second spring members 42 and 44 of thecontacts 40 are clamped between the wall surfaces 38a and 38b and thecontact sections 82 of the contacts 80. Furthermore, when the contactprojections 44a of the second spring members 44 are pressed against thecontact sections 82 of the contacts 80, the first and second springmembers 42 and 44 apply a force on the contacts 80. Thus, when the plugconnector 20 and cap connector 60 are connected, the contacts 40 areclamped between the wall surfaces 38a and 38b and the contacts 80 andare strongly pressed against both the wall surfaces 38a and 38b andcontacts 80. Accordingly, even if the contacts 40 are made smaller andshorter in order to reduce the pitch of the contacts 40, the contacts 40and contacts 80 electrically and wipingly contact each other with a highcontact pressure. Furthermore, since the contacts 40 are arranged in tworows so that the first and second spring members 42 and 44 of thecontacts 40 are mutually symmetrical in the opposing rows, therespective forces between contacts 40 and 80 are balanced between therows of contacts 40, so that the contacts 40 and contacts 80 contacteach other with a high well-balanced contact pressure, thus making itpossible to obtain an electrical connector that provides secureelectrical connections.

A second embodiment of the electrical connector of the present inventionwill be described with reference to FIGS. 12-15:

The electrical connector of the second embodiment is characterized bythe shape of the cap connector. The plug connector has the same shape asthe plug connector in the first embodiment. Accordingly, the capconnector will be described here.

The cap connector 90 is equipped with a housing 100 and contacts 120.The contacts 120 are lined up in two rows along the length of thehousing 100. Compared to the contacts 80 of the cap connector 60 shownin FIGS. 6-9, the contacts 120 are longer with a length of approximately9.00 mm. The housing 100 is equipped with posts 102 and 104 that arerespectively inserted into post holes 14a and 14b formed in the board 14and a metal-fastening fitting or hold down 106 that is soldered to afastening pad 14c on the board 14. Furthermore, side walls 108 extend inthe direction of the length of the housing 100 and are formed withopenings 108a. These openings are a characteristic feature of the capconnector 90. The reason for forming the openings 108a will be describedbelow.

The housing 100 is ordinarily made of a synthetic resin and is formed byinjection molding using a mold that corresponds to the shape of thehousing 100. The contacts 120 are inserted into the housing 100 afterthe housing 100 has been molded. The spaces into which the contacts 120are inserted are formed in the injection-molded walls of the housing 100using long, slender pins known as core pins. After the housing 100 hasbeen injection-molded, these core pins are removed from the housing 100.In cases where the contacts 120 are long, the core pins are alsonaturally long, so that there is a danger that bending will occur whenthe core pins are pulled out of the housing 100. Accordingly, theopenings 108a are formed in the side walls 108 of the housing 100 inorder to allow shortening of the core pins even in cases where thecontacts 120 are long. By thus forming the openings 108a, it is possibleto use a metal mold in the areas corresponding to the openings 108aduring injection molding. Furthermore, two short core pins that arerespectively inserted from above and below are used in each areacorresponding to a space into which one of the contacts 120 is to beinserted. By thus using two short core pins to form spaces for theinsertion of long contacts, it is possible to prevent bending of thecore pins when they are pulled out of the housing 100 followinginjection molding.

A third embodiment of the electrical connector of the present inventionwill be described with reference to FIGS. 16-18.

The electrical connector 128 of the third embodiment is characterized byshield plates 170 that are attached to the side surfaces of walls 158 ofthe housing 152 of the cap connector 150 and by the shape of the groundcontacts among the contacts of the plug connector.

The electrical connector 128 of the third embodiment is equipped with aplug connector 130 and a cap connector 150 that are substantiallysimilar in shape to the plug connector 20 and cap connector 60 of theelectrical connector 10 of the first embodiment illustrated in FIGS. 1through 11. Ground contacts 134 and signal contacts 136 are arranged inthe housing 132 of the plug connector 130. Furthermore, ground contacts154 and signal contacts 156 are also arranged in the housing 152 of thecap connector 150. Moreover, shield plates 170 are respectively attachedto both side surfaces of walls 158 of the housing 152 of the capconnector 150. This attachment is accomplished by causing the shieldplates 170 to slide relative to the housing 152 so that respectiveprojections 158a formed on the side surfaces of walls 158 enter thenarrow portions 172a of openings 172 formed in the shield plates 170.Bridge contact sections S1 (supported at both ends) on which dimples 174are formed and tongue members S2, which are used to make spring contactwith the ground contacts 154 of the cap connector 150, are formed on theshield plates 170.

When the plug connector 130 and a cap connector 150 are connected, thebridge contact sections S1 of the shield plates 170 contact theextensions 134a of the ground contacts 134, and the tongue members S2springably contact the termination sections 154a of the ground contacts154. If necessary, the tongue members S2 and the termination sections154a of the ground contacts 154 may be soldered. Furthermore, in theassembly process, the termination sections 154a of the ground contacts154 are soldered to the conductive pads 14d on board 14. Accordingly,the heat generated when the cap connector 150 is mounted on the board 14may be utilized in order to solder the tongue members S2 and thetermination sections 154a of the ground contacts 154. As is shown inFIG. 18, the signal contacts 136 and 156 do not contact the shieldplates 170. Furthermore, the housing 152 of the cap connector 150 hasprojecting portions 159 and grooves 160 that accommodate the projectingportions 138 of housing 132 at which the contact sections S1 andextensions 134a are located. The assembly process is as follows: Theshield plates 170 are first attached to the housing 152 of the capconnector 150, after which the contacts 154 and 156 are positioned intothe housing 152. Soldering is performed only when the cap connector 150is attached to the board. Dimples 174 are formed in the shield plate170, and these dimples 174 electrically contact the extensions 134a ofthe ground contacts 134. However, it would also be possible to omit thedimples 174. In the electrical connector of this third embodiment, aswas described above, the respective ground contacts 134 and 154 caneasily be connected by attaching a single shield plate 170 to thehousing 152 of the cap connector 150.

FIG. 19 illustrates a fourth embodiment of the electrical connector ofthe present invention. The difference between this electrical connectorand the electrical connector of the third embodiment lies in the shapeof the shield plates. In the shield plates 180 of the electricalconnector of this fourth embodiment, no projections are formed in thetongue members in order to prevent sagging of the slots 182. An effectsimilar to that obtained using the shield plates 170 shown in FIG. 16can also be obtained using these shield plates 180.

In the electrical connector of the present invention, as was describedabove, the first contacts are clamped between the wall surfaces and thesecond contacts and are thus strongly pressed against both the wallsurfaces and the second contacts, when the first and second connectorsare connected to each other. Accordingly, even in cases where thecontacts are made smaller and shorter in order to reduce the pitch ofthe contacts, the first contacts and second contacts can be caused toelectrically contact each other with a high contract pressure.Furthermore, since the first contacts are lined up in two rows so thatthe first and second spring members are mutually symmetrical in theopposing rows, the respective forces from the wall surfaces and thesecond contacts are balanced between the two rows, so that the firstcontacts and second contacts can be electrically connected to each otherwith a high, well-balanced contact pressure, thus making it possible toobtain an electrical connector that provides a secure electricalconnection.

I claim:
 1. An electrical connector for electrical connection toconductive pads on board members comprising a plug connector havingelectrical contacts secured in a plug housing and including contactsections and termination sections for electrical connection to theconductive pads on one of the board members and a cap connector havingelectrical contacts with a linear configuration secured in a cap housingand including contact sections electrically connecting with the contactsections of the plug connector when the plug connector and cap connectorare mated together and termination sections for electrically connectingwith the conductive pads of the other of the board members, wherein:eachcontact of the plug connector includes a base portion having abeamextending upwardly therefrom, the beam including a contact sectionthereon for mating with a corresponding linear contact of the capconnector, the beam further including a spring portion extending from anend thereof, the spring portion including an arm extending to a curvedspring end portion with the arm extending along a central wall of theplug housing; whereby upon mating the plug and cap connectors, thecurved spring end portions press against the central wall of the plughousing such that the spring portions of the contact sections of theplug connector are springably clamped between the linear contactsections of the cap connector and the wall of the plug housing.
 2. Theelectrical connector of claim 1, wherein the base portion of eachcontact of the plug connector is connected to the termination section.3. The electrical connector of claim 1, wherein the spring portion hasan S-shape and the end portion engages the central wall.
 4. Theelectrical connector of claim 1, wherein shield plates extend alongsurfaces of the cap housing, and ground contacts are secured in the caphousing and are in electrical connection with the shield plates.
 5. Theelectrical connector of claim 1, wherein the beams have a contactprojection that electrically contact the linear contact.
 6. Anelectrical connector having a plug and a cap, the connector comprising:aplug housing having sidewalls and a central wall therebetween; aplurality of contacts disposed between the sidewalls and the centralwall, each contact including a base portion, the base portion having abeam extending upwardly from the base portion between the sidewalls andthe central wall, a contact section disposed on the beam, and a springportion extending from the beam including an arm having a curved endportion extending along the central wall; and a cap housing havingplurality of linear contacts disposed along parallel walls, the linearcontacts contacting the beams and compressing the spring portionsbetween the linear contacts and the central wall, and wherein thesidewalls of the plug and the parallel walls of the cap engage eachother at free ends when the cap and plug are mated.
 7. The electricalconnector of claim 6, wherein the beam has contact projections thatelectrically contact the linear contacts.
 8. The electrical connector ofclaim 6, wherein the spring portion has an S-shape.
 9. The electricalconnector of claim 6, wherein shield plates extend along surfaces of thecap housing, and ground contacts are secured in the cap housing and arein electrical connection with the shield plates.